<template>
  <div :class="className" :style="{height:height,width:width}" />
</template>

<script>
// 按需引入 引入 ECharts 主模块
var echarts = require('echarts');
// 引入柱状图
require('echarts/lib/chart/bar')
// 引入提示框和标题组件
require('echarts/lib/component/tooltip')
require('echarts/lib/component/title')
import chartResize from './mixins/chart-resize'

export default {
  mixins:[chartResize],
  name:'Bar-chart',
  props: {
    className: {
      type: String,
      default: 'chart'
    },
    width: {
      type: String,
      default: '100%'
    },
    height: {
      type: String,
      default: '350px'
    },
    // 父组件传递过来的图表数据
    chartData: {
      type: Object,
      required: true
    }
  },
  data() {
    return {
      // Echarts实例
      chart: null
    }
  },
  watch: {
    /* 如果图表数据是后台获取的，监听父组件中的数据变化，重新触发Echarts */
    chartData: {
      deep: true,
      handler(val) {
        this.setOptions(val)
      }
    }
  },
  mounted() {
    /* 图表初始化 */
    this.$nextTick(() => {
      this.initChart()
    })
  },
  beforeDestroy() {
    if (!this.chart) {
      return
    }
    /* 释放图表实例 */
    this.chart.dispose()
    /* dispose 会释放内部占用的一些资源和事件绑定，但是解除实例的引用我们是做不到的，所以需要重新赋值为null */
    this.chart = null
  },
  methods: {
    initChart() {
      this.chart = echarts.init(this.$el)
      this.setOptions(this.chartData)
    },
    setOptions({ days, data1, data2 } = {}) {
      this.chart.setOption({
        title: {
          text: '堆叠柱状图',
          textStyle: {
            fontSize: 15
          }
        },
        tooltip: {
          trigger: 'axis',
          axisPointer: { // 坐标轴指示器，坐标轴触发有效
            type: 'shadow' // 默认为直线，可选为：'line' | 'shadow'
          }
        },
        grid: {
          top: 35,
          left: '2%',
          right: '2%',
          bottom: '3%',
          containLabel: true
        },
        xAxis: [{
          type: 'category',
          data: days,
          axisTick: {
            alignWithLabel: true
          }
        }],
        yAxis: [{
          type: 'value',
          axisTick: {
            show: false
          }
        }],
        series: [{
          name: '数量一',
          type: 'bar',
          stack: 'vistors',
          barWidth: '60%',
          data: data1,
          animationDuration:2000
        },
        {
          name: '数量二',
          type: 'bar',
          stack: 'vistors',
          barWidth: '60%',
          data: data2,
          animationDuration:2000
        }]
      })
    }
  }
}
</script>
